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Vestibular Evoked Myogenic Potentials in Delayed Endolymphatic Hydrops
Author(s) -
Young YiHo,
Huang TsungWei,
Cheng PoWen
Publication year - 2002
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200209000-00018
Subject(s) - endolymphatic hydrops , vestibular evoked myogenic potential , saccule , audiology , caloric theory , medicine , paresis , vestibular system , caloric test , meniere's disease , surgery , vertigo
Objective/Hypothesis Vestibular evoked myogenic potential (VEMP) has become an established test to explore the sacculo‐collic reflex. The study aims to investigate the VEMPs in cases of delayed endolymphatic hydrops because greatly dilated saccule was observed in histopathological specimens of delayed endolymphatic hydrops. Study Design Prospective study. Methods Twenty patients with delayed endolymphatic hydrops were subjected to pure‐tone audiometry, caloric testing, and VEMP test. Delayed VEMP was defined as the latency of peak I exceeding 22.6 milliseconds or of peak II exceeding 33.1 milliseconds. Interaural amplitude difference over the sum of amplitudes of both ears was measured, and when the ratio exceeded 0.36, it was identified as augmented VEMP or depressed VEMP depending on whether the amplitude of the lesioned side was greater or less than the opposite side. Results The VEMP test revealed that 9 patients (45%) were normal, 6 (30%) exhibited absent VEMPs, and 5 (25%) displayed abnormal VEMPs, including delayed VEMPs in 2, depressed VEMPs in 2, and augmented VEMPs in 1. The caloric test indicated that 9 (47%) of the 19 ears exhibited normal caloric response, whereas 10 ears displayed abnormal caloric responses including canal paresis in 8 and absent caloric response in 2. Six ears had preserved both the caloric response and the VEMPs, whereas no ear demonstrated both absent caloric response and absent VEMPs. Conclusions The residual caloric as well as saccular functions after ear insult may determine whether delayed endolymphatic hydrops will occur. These findings suggest that patients with sudden deafness or juvenile unilateral total deafness should undergo caloric testing and VEMP test to predict the occurrence of delayed endolymphatic hydrops in the future.